1. Field of the Invention
The present invention generally relates to a drag mechanism. More specifically, the present invention relates to a drag mechanism configured to brake a rotation of the spool.
2. Background Information
In order to reduce a tensile force acting on a fishing line, some spinning reels are provided with a mechanism configured to brake the spool. Such mechanisms are called drag mechanisms. One widely used type of drag mechanism is a front drag mechanism, which is housed inside a drag housing recess formed inside a bobbin trunk onto which the fishing line is wound. A front flange is arranged on a frontward end of the bobbin trunk. The front flange is provided either as an integral part of the bobbin trunk or as a separate entity. One known method of fastening the front flange to the bobbin trunk when the front flange is provided as a separate entity is to use a flange fastening member. The flange fastening member is fastened to the bobbin trunk by being screwed into an internal circumferential surface of a frontward portion of the drag housing recess (see, for example, Japanese Patent Publication No. 2002-345369).
In a conventional spinning reel, a portion of the flange fastening member that screws into the drag housing recess has a cylindrical section on an external circumferential surface. An externally threaded section is formed on the external circumferential surface. The externally threaded section mates with an internally threaded section formed on an internal circumferential surface of the bobbin trunk. Since the flange fastening member is screwed into the internal circumferential surface of the bobbin trunk instead of fastened with bolts, it is not necessary to provide bolt holes between an outside edge of the bobbin trunk and the drag housing recess. As a result, a wall thickness of the bobbin trunk is reduced and an internal diameter of the drag housing recess is increased, thereby enabling a larger drag force to be obtained due to a larger drag diameter. In particular, in a deep groove spool in which a difference between external diameters of the front flange and the bobbin trunk is large, the internal diameter of the drag housing recess is smaller than in a shallow groove spool. Using a flange fastening member that screws into the drag housing recess makes it easier to increase the drag diameter and obtain a larger drag force in deep groove spools.
The conventional front drag mechanism has one or more drag washers and a drag knob. The one or more drag washers are housed inside the internal circumference of the spool. The drag knob is configured to screw onto the frontward end of the spool shaft. The drag knob is configured to enable the amount of pressure applied to the one or more drag washers to be adjusted. The drag washers include a first drag washer and a second drag washer. The first drag washer is arranged such that it is non-rotatable with respect to the spool. The second drag washer is arranged such that it is non-rotatable with respect to the spool shaft. The first and second drag washers are arranged alternately. A pair of interlock protrusions configured to engage with interlock grooves formed in the internal circumferential surface of the drag housing recess is provided on an external circumference of the first drag washers. The interlock protrusions protrude radially outward from the external circumferential surface of the first drag washer and are arranged on diametrically opposite sides of the first drag washer. The first drag washer is rendered non-rotatable with respect to the spool due to the engagement of the interlock protrusions with the interlock grooves. Parallel, axially chamfered sections are formed on the frontward end of the spool shaft and an oval interlock hole configured to engage with the chamfered sections is formed at the center of the second drag washers. The second drag washer is rendered non-rotatable with respect to the spool shaft due to the engagement of the interlock hole with the chamfered sections.
Thus, when assembling a spool in which the front flange is fastened using a flange fastening member that screws into the bobbin trunk of the spool, the drag washers are installed into the drag housing recess after the flange fastening member is installed into the bobbin trunk. For example, consider a case in which a second drag washer is installed and then a first drag washer is installed such that the interlock protrusions engage with the interlock grooves of the drag housing recess. Since both drag washers must be passed through the tubular section on which the externally threaded section of the flange fastening member is provided, the external diameters of the drag washers must be smaller than the internal diameter of the tubular section. Consequently, the internal diameter of the internal circumferential surface of the drag housing recess where the two interlock grooves are formed is considerably smaller than the internal diameter of the tubular section of the flange fastening member.
In the conventional structure described above, the internal diameter of the drag housing recess is smaller than the internal diameter of the flange fastening member so that the first drag washer, which has the pair of interlock protrusions arranged on opposite sides thereof, can be installed. Consequently, the drag diameter is small and it is difficult to obtain a larger drag force. If the internal diameter of the drag housing recess were made to be the same as the internal diameter of the tubular section, the first drag washer would have to be tilted to a great degree when passing it through the tubular section of the flange fastening member in order for the two diametrically oppositely arranged interlock protrusions to fit through. Consequently, the longitudinal dimension of the drag housing space (length of the drag housing space along the axial direction of the spool) would have to be longer in order to accommodate the larger longitudinal length that the first drag washer assumes when it is tilted in order to install it. Furthermore, the number of draw washers would have to be smaller or, if the longitudinal dimension of the drag housing recess is small, it might not be possible to install a first drag washer at all. Therefore, when the longitudinal dimension of the drag housing recess is short, the conventional structure requires the internal diameter of the drag housing recess to be smaller than the internal diameter of the tubular section of the flange fastening member and, thus, does not allow the internal diameter of the drag housing recess to be increased.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved spinning reel drag mechanism that maximizes an internal diameter of a drag housing recess. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.